Double-walled strainer for culverts, drainage-casings, &amp;c., and connecting means therefor.



A. SMITH.

DQUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, 610., ANDCONNECTING MEANS THEREFOR.

APPLICATJION FILED JULY 29, 1913.

1,165,137, I Patented Dec. 21, 1915.

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DOUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, &c., ANDCONNECTING MEANS THEREFOR.

APPLICATION FILED JULY 29, 1913.

1,165,137. Patented Dec. 21, 1915.

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DOUBLE WALLED STRAINER FOR CULVERTS, DRAINAGE CASINGS, 810., ANDCONNECTING MEANS THEREFOR.

APPLICATION FILED JULY 29, 1913.

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' APPLICATION HI E'D'IULY 29,1913- Patented Dec. 21, I915.

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3 mm; a QQQQUQQQ Q1 Q Emu) v A. SMITH. DOUBLE WALLED STRAINER FORCULVERTS, bRAINAGE CASING S, & c., AND CONNECTING MEANS THEREFOR.

' APPLICATION FILED JULY 29. 1913.

Patented Dec. 21, 1915.

5 SHEETS-SHEET 5 UNITED STATES PATENT OFFICE.

ANDREW SMITH, OF SAN MATEO, CALIFORNIA.

DOUBLE-WALLED STRAINER FOR CULVERTS, DRAINAGE-CASINGS, 850., AND

CONNECTING MEANS THEREFOR.

To all "whom it may concern:

Be it known that L-ANDREW SMITH, a citizen of the United States,residing at San Mateo, in the county of San Mateo and State of,California, have invented certain new and useful Improvements-inDouble-\Valled Strainers for Culverts, Drainage-Casings, &c., andConnecting Means Therefor, of which the following is a specification.

This invention relates to perforated casings for use in culverts,drainctiles, wellstrainers, or curbing, etc., andits' object is toprovide a casing section-having airintegral, intermediate duplexdraining -or strainer portion.

A further object is to. provide acasing section. having an intermediatedoublewalled draining portion and single-walled terminal end portionswhich may be connected by threaded union members or otherv connectingmeans with the ordinary culvert, well, or other drainage casings.

It is frequently desirable to introduce draining sections into a line ofculvert pipe or well casing. \Vhile such drainage section may comprise asingle-walled perforated or slitted pipe, yet I have found that adouble-walled casing is much more effective in securing an increaseddrainage capacity and is less liable to become clogged by thesurrounding earth, sand and gravel. Vhen a casing is drilled with holesor otherwise perforated, the metal walls are necessarily much weakenedbut by my invention the perforated inner casing is strengthened by theouter perforated strainer portion which is welded or riveted to theinner casing 'so that the whole becomes an integralunit.

I The perforations-are confined .to .the. doublewalled portion, thesingle-walled ends'being imperforate.

The structural feature of my invention and-the advantages which arederived from its use will be understood from the follow ing descriptionin connection with the accompanying drawings, in which Figure 1is anelevation of a casing partly in section, embodying my invention; Fig. 2is anelevation of a casing showing one of my preferred forms of threadedconnections; Figs. 3 to 28, inclusive, illustrate various embodiments ofmy invention.

Referring to Fig. 1, th casing section .of the punched metal parts.

Specification of Letters Patent. Patented Dec, 21, 1915, Appllcatlo ifiled July 29, 1913. Serial No. 781,820.

comprises a main casing member 2, which I have illustrated as havingthreaded terminal portlons to receive ordinary coupling unions 3, and anintermediate portion provided with perforations which may be in the formof holes'drilled or punched or sheared there- 1n. The outer member '7 ofthe duplex drainage portion which is slid over the perforated portion ofthe main casing is prefer- I ably asingle tube but I may form it .of twosimilar parts which abut at the center, the

abutting flanges 9 beingwelded together, or,

parts may be riveted together to make an integral structure, as shown at10, Fig. 3, but it is far preferable to weld them.

The outer element or member 7 is provided with narrow sheared slits toform a screen or strainer. In the shutter-like forms shown in Figs. 1,6, 12, 14 and 22, the slits are bounded by the inner edges of the outerlips and the outer edges of the inner lips 14 The slits are preferablyfirst formed in the sheet metal, from which the casing is constructed,by shearing the metal in the manner disclosed in my prior Patents Nos.1,027,917, 1,028,066 or 1,055,615. The slits formed in accordance withthe processes of my said prior patents are practically smooth-walled andmay be thoroughly protected from corrosion by galvanizing, sherardizingor other coating process, and the width of the slits may be made asnarrow as desired. depending upon the character of the formations inwhich the drain casing is to be embedded.

The sheared sheets are bent into tubular form and welded at the seam orjoint to form tubular sections, but it is obvious that the narrow slotsmay be formed by perforating the casing. I prefer to form the outermember, or slip-over portion, of' each cas-.

ing section of a continuous length of sheared tube or pipe, making itnecessary only to weld the ends 8 to the main casing.

.use larger apertures in the inner wall.

The elongated narrow slits in the outer- .13, .15, 19 and 23, the inneredges of the inturnedlips 14, may be constructed to bear against theinner. casing and maintain the inner and outer" walls spaced .apartsufliciently to insure a 'free unobstructed passage of the water oroilentering through v outer strainer casing or screen.

The main casing 2 is constructed from heavy sheet metal and can be madeof noncorrosive material. The outer slip-over member 7, which isprovided with practically smooth-walled shearedslits, isusually ofthinner sheet metal and may be made of brass, copper or othernon-corrosive metal,

or other metals may be used and galvanized or otherwise coated toprotect from corrosion. The casing sections or units may be threadedupon either end in the usual manner with the threads either cut orrolled into the metal, as illustrated at 2 in Fig. 1, and be connectedby means of threaded unions or coupling rings 3. In this form ofcoupling in which; the threads are cut into the metal, the walls of thepipe are weakened and the strength of the joint depends upon thecomparatively shallow threads. The strength of such couplings is notover per cent. of the strength of the casing at other points.

In order to provide ameans for handling the sectional units withoutinjury to the perforated portions, when they are being laid in an openditch or being'forced through a tunnel in constructing a culvert or whenbelng lowered by elevators into the bore of 'a well, I leave a plainportion 2 between the duplex strainer portion and the corrugated orthreaded end portion. The outer 'caslng member is preferably formed withplain end portions 8 for a distance of a few inches to providereinforced plain portions,

At these plain pipe portions. the tongs, clamps'or elevators may beattached. The spiral corrugations or threads at the ends are alwaysformed so that the sections will be turned *in a right-hand orclock-wise di-.

rection, in order that none of the sections may become disconnected. Forthis reason I arrange the lipsof the perforations in the arrangementsshown in Figs. 1, 12, 14 and 23, so that they extend in a left-handdirection and when the casing is rotated in a right-hand direction theperforations will not be'comeclogged with earth, as would evidently bethe case if they pointed in the opposite direction.

As previously stated, the outer slitted portion forms a strainer andalso a reinforcement for the inner perforated member. The slits in theouter member 7, are made'to allow the very fine particles of earth toflow side of each shear cut may be forced inwardly as shown in- Figs.12, 13, 18 and 19; or opposite sides of the cut may be forced inopposite directions as in Figs. 14 and 15. Under some conditions itmaybe desired to have a perfectly" smooth exterior and the slits maybeformed by spreading the metal upon either side of a'row of slits asinFig. 3. The process of forming these slits is disclosed in my PatentsNos. 1,027,917 and 1,028,066, dated May 28, 1912 and No.

1,055,675 dated March 11, 1913. The slits are preferably \l-shaped incross-section, with the narrower side outward so that the ing is to besubjected. The metal upon one slit will gradually increase in width fromthe outer to the inner side ofthe casing as shown in the outer casing inFigs. 17 and 21. With this construction the slits are not liable tobecome'clogged since any small particles of sand that pass into the slitwill immediately pass into a larger opening and cannot wedge or bindbetween the sides of the slit.

Another method of forming slits is by forcing alternate strips of metalbetween the slits inwardly as shown at 16 in Figs. 1 and 5. In thisconstruction the slits are formed between the edges of the forced-instrips 16? of the casing, which also serve to stiffen the casing. It isobvious that the perforated casing may be formed by bending the sheet'in the reverse direction so that the sheared strips which have. beenforced slightly out of the plane of the sheet will extend outwardly ofthe'casing. The slits may also be formed by forcing adjacent alternatestrips inopposite directions', as indicated in Figs. 10 and 11. Theparallel slits 17, thus formed may be made as narrow as desired forstraining purposes,

as it is only necessary for the metal strips to be forced to one sideslightly morethan halfthe thickness of the metal. This constructionforms an exceedingly efiicient fully disclosedin myPatent No. 1,057,098

dated March 25, 1913. This form of slitted casing increases the drainingcapacity without decreasing the strength of the casing.

I have shown the slitted strainer member placed upon the outside of theinner casing which extends beyond ,the strainer member at the ends, butunder some conditions the strainer member may be placed inside of themain casing member and become the inner part of the double-walledintermediate portion as illustrated in Fig. 26, and this arrangement isincluded within the scope of my claims. The casing may be made morerigid by means of corrugations 20 between the series of slits, which mayextend circumferentially as in Figs. 12 and 16, or spirally as in Fig.8/ It will be observed that the corrugations bear against the inner pipeand maintain the outer slitted "member spaced away from the innermember, thereby insuring an unobstructed passage for the water from theoutside to the inside of the casing. The slits may extend into thecorrugations in order to provide a passage for the fluids to flow aroundany obstructions that may be against the strainer.

\Vhile it is preferable that the slits should extend longitudinally "ofthe casing since this construction offers less resistance as.

the casing is. being forced into the bore of the earth during theconstruction of a culvert, draining .tunnel or well, 'yet under someconditions it-may be desirable to ar-. range the slots horizontally inlongitudinal series as illustrated in Figs. 6 and 18. It is evident thatinstead of punching the holes in the inner casing, I may perforate itwith sheared slits in the same manner as the outer member is slitted.The lips adjacent the slits in the outer member may be pressed inwardlyand those in the inner casin'gmay be pressed outwardly. and thelongitudinal I series of the inner and outer casing members mavalternate or interfit with each other in staggered relation, asillustrated in Fig.28. It isto be understood, therefore, that my claimscover constructions in which the outer and inner casing members are bothprovided with sheared slits. or either may be provided with shearedslits and the other with punched holes. Furthermore, it is to becomeclogged with evident that this arrangement of slitted or slitted andpunched members may be applied to casings which are double-walledthroughout their extent. The slits may also be arranged in other ways,as for instance, 1n sp1ral series as shown in Fig. 22. The

corresponding cross-sectional views adjacent each side elevation willmake the construc-' tions clear.

I have referred to the single-walled end portions as being imperforateyet there may be conditions in which it is desirable to also provide 1perforations in the end portions and it is to beunderstood. that suchcon structions come within the scope of my broader claims. I also regardas within the purview of my invention claimed herein, a construction inwhich the ends of the outer slip-over strainer member are extended asfar as the connecting collars or .otherconcorrugations which I havedescribed in connection with Figs. 10 and'20, may be applied to animperforate pipe, conduit, drain tile, culvert or well casinghavingeither plain or corrugated walls, or to a single-walled perforatedcasing. In Fig. 2, I have illustrated my reinforced spirally corrugatedend connection applied to a single-walled culvert or well strainercasing provided with my shutter-like sheared slits.

I have described in detail the various modifications shown in thefigures. of the accompanying-drawings for the purpose of illustratingspecific embodiments of my invention, but it is evident that variouschanges may be made therein without departing from the spirit of myinvention. I have shown in the various drawings anouter strainer memberhaving narrow sheared slots therein but it is obvious that this strainermember may be used as an inner section.

The advantages to be derived from the use of my invention disclosedherein in' which each. sectional unit is an inte a1 structure and inwhich the intermedlate strainer portion comprises duplex walls whichmutually reinforce each other, while the whole presents a comparativelysmooth unobstructed exterior surface, will be appreciated by engineers.I

I claim 1. A sheet metal casing for culverts, wells and drainagepurposes, comprising sectional Thus in Fig. 27, it is evident I anddrainage purposes, comprising sectional units having an.lntermediateportion prounits having an intermediate portion pro-' videdwith double walls weld-united at the ends of said portion and each ofwhich is perforated, and imperforate single-walled end portions.

2. A sheet meta-l casing for culverts, wells,

vided with double walls rigidly united at the ends of said portion,andeach of which is perforated, the perforations in the outer wallbeingnarrow sheared slitsand the perforations in the inner wall beinglarger than those in the outer wall.

3. A sheet metal casing for culverts, wells and drainage purposes,comprising a tubu- 'lar memberhaving an intermediate portion provided.wlth double walls, each of which is'perforated, and spirally corrugatedend portions, one end being tapered and the other end beingcorrespondingly flared so that the tapered end of one section may bescrewed into the flared end of another sect1on.

4. A sheet metal casing for culverts, wells and drainagepurposes,rcomprising a tubular member havln I an intermediate portionprovided with dou 1e walls which are weldunited, each of which isperforated, and single-walled end portions, and means for connectingadjacent casing sections together.

5, A sheet metal casing for culverts, wells and drainagepurposes,'comprising a tubular memberhavin g an intermediate portionprosaid perforated intermediate portion.

ber provided with narrow. sheared slits, and

extending concentrically over said intermediate portion and having itsends rlgidly secured to said tubular member, the stralner member therebyforming a reinforce for 7. A sheet metal casing for culverts, wells anddrainage purposes having double walls,

each of which is perforated and the perforations in one of the wallsbeing narrow sheared slits.

8, A sheet metal casing for culverts, wells and drainage purposes havingdouble walls with sheared 'slitsin one of the walls, portions of-saidwalls being spaced apart, thereby establishinga passageway for the fluidlengthwise of the drainage section.

In testimony whereof I affix my signature in presence of two witnesses.

, ANDREW SMITH.

Witnesses JAMES F. Ross, GUSTAV A. HERBST.

